EGR Valve Position Sensor: Description and Operation

Exhaust Gas Recirculation System (EGR):

The exhaust gas recirculation system introduces exhaust gas into the intake manifold to reduce NOx emissions. The system comprises the EGR control valve, EGR position sensor, duty solenoid valve, and the emission control unit.

EGR VALVE

The EGR control valve controls the the amount of exhaust gas flowing into the intake manifold, according to vacuum regulated by the duty solenoid valve.

EGR POSITION SENSOR

The EGR position sensor detects the position of the EGR control valve and sends a signal to the emission control unit.

DUTY SOLENOID VALVE

The duty solenoid valve consists of a vacuum valve and a vent valve. The vacuum valve opens the vacuum passage to the EGR control valve, and the vent valve vents the vacuum from the vacuum valve to control vacuum according to signals from the emission control unit.

ENGINE CONTROL UNIT

The engine control unit senses the amount of EGR gas recirculated by the EGR position sensor on the EGR valve and controls the opening duration of the vacuum and vent valves. The amount of exhaust gas recirculation is determined by the ignition coil signal, coolant temperature sensor, vacuum sensor, coolant temperature switch, and atmospheric pressure sensor.